Structured Packing

[eljefe3126]

In the chemical industry, this is what they call structured packing. It's layers of metal gauze (or plate), crimped into v-shaped corrugations at an angle to vertical of 45-60 degrees. Then each layer is placed back-to-back with the previous layer, so that droplets can bounce left or right as they descend like pinballs in a pachinko machine. The round bands have tabs that intercept droplets clinging to the wall of the column and redirect them to the interior where the packing is.

Has anyone here experimented with this stuff? It seems like it would be easy to make if one just had a means of corrugating strips of metal gauze.

[OtisT]

I went looking to buy something like this years back, something I could slip whole into a column, but I could not find anything small enough for hobby size columns. It was all industrial size stuff. I wish you better luck than I had in my search.

[StillerBoy]

I'm of the view there's to much open space, plus the band with the tabs really serve nothing, as the distillate will just follow the inside the band instead of the column.. waste of time and funds compared to some other packing doing a good job for the hobbyist..

Packing need to have the least amount of open space between the them for it to work at maximum efficient..

Mars

[shadylane]

Packing need to have the least amount of open space between the them for it to work at maximum efficient..

I disagree.

"Packing materials must meet a few requirements to perform effectively. They must not interact chemically with the fluids being packed. They must be strong but lightweight. They must contain enough passageways that the liquid material can flow through without obstructing the liquid or causing drops in pressure. They must also allow for the proper amount of contact between liquid and gas."


https://www.machengineering.com/random- ... d-packing/

[Saltbush Bill]

Nice link Shady , some interesting reading.

[Stonecutter]

Nice link Shady , some interesting reading.

+1
Just took a brief look. It reads easy enough.


Shady I like that quote from the link

without obstructing the liquid or causing drops in pressure. They must also allow for the proper amount of contact between liquid and gas."


https://www.machengineering.com/random- ... d-packing/

To focus on a single variable in order to maximize efficiency would be folly.

First you’ve got the critical selection of packing material.

And Pressure drop and liquid obstruction are intertwined with the “open space” within the column.

It gets so easy to simplify a relatively complex function like reflux because so much experimentation has been documented here already.

[StillerBoy]

It gets so easy to simplify a relatively complex function like reflux because so much experimentation has been documented here already.

What is a "relatively complex function like reflux" mean to the hobbyist..

Refuxing is a simple activity.. it's balancing the power used with the take off rate in relation to the packing used for the highest ABV possible.. different packing material require different setting or dialing in, providing different take off rate and ABV levels..

To simplify it at the hobbyist level means the usage of a packing that provide the maximum ABV with the lease power usage and maximum take off rate in the lease amount time..

The two packing that provide such, that provide such for the hobbyist, is lava rocks of the right sizing and SSP.. yeah there are other material that "work" as packing material but are not nearly as good as those mention..

Do or take the time to do such, and determine for one self, we are hobbyist first and not working to match what professionals are doing, which in large part is what the article was written for..

Mars

[Stonecutter]

Packing need to have the least amount of open space between the them for it to work at maximum efficient..

Mars

Refuxing is a simple activity..

To simplify it at the hobbyist level means the usage of a packing that provide the maximum ABV with the lease power usage and maximum take off rate in the lease amount time..


Do or take the time to do such, and determine for one self, we are hobbyist first and not working to match what professionals are doing, which in large part is what the article was written for..

Mars

So which is it? Power usage and takeoff rate or space between packing?

[shadylane]

the band with the tabs really serve nothing, as the distillate will just follow the inside the band instead of the column.. .

Mars

I disagree about the bands and tabs being useless.
Once upon a time folks were using centering rings to do the same job.
But everyone was using rings that were too big and causing localized flooding.

[StillerBoy]

So which is it? Power usage and takeoff rate or space between packing?

I can see being inexperience can cause one to question.. time will develop experience, then it will all come together..

Mars

[Salt Must Flow]

I'd say, unless someone has tried it and reports back then it's all just speculation. Doesn't that make sense? Even if one person tried it, it's just anecdotal evidence. Considering the cost of structured packing, I'd just use Lava Rock and/or make my own SPP like StillerBoy said.

Who knows ... maybe some company will start up and make laser sintered 3D printed structured packing out of stainless and copper for a reasonable price with performance data to back it up. Wouldn't that be cool.

[StillerBoy]

I disagree about the bands and tabs being useless.
Once upon a time folks were using centering rings to do the same job.
But everyone was using rings that were too big and causing localized flooding.

Yeah they were ideas from inexperienced hobbyist with no consideration, and over time the idea fell by the roadway, but there are still a few inexperienced who belief they do good..

Any attempt at making the returning distillate to travel down the center by using tabs or centering rings, no matter what size used, is a total waste of effort..

Distillate will take the easiest path down, and centering ring just disrupt for a few mm only and create some lost of performance.. and the other reason is that boiler and column are never truly level, and the distillate will always travel to the off angle side.. something that is never talked about, being on level went refluxing..

Mars

[Stonecutter]

So which is it? Power usage and takeoff rate or space between packing?

I can see being inexperience can cause one to question.. time will develop experience, then it will all come together..

Mars

Oh I see.

Well, I’m glad it makes so much sense to you StillerBoy. Maybe one day, I’ll be so knowledgeable that I’ll be able to chew my food twice just like you can. Then it will ALL come together.

[Salt Must Flow]

I disagree about the bands and tabs being useless.
Once upon a time folks were using centering rings to do the same job.
But everyone was using rings that were too big and causing localized flooding.

Yeah they were ideas from inexperienced hobbyist with no consideration, and over time the idea fell by the roadway, but there are still a few inexperienced who belief they do good..

Any attempt at making the returning distillate to travel down the center by using tabs or centering rings, no matter what size used, is a total waste of effort..

Distillate will take the easiest path down, and centering ring just disrupt for a few mm only and create some lost of performance.. and the other reason is that boiler and column are never truly level, and the distillate will always travel to the off angle side.. something that is never talked about, being on level went refluxing..

Mars

I don't think the vast majority of home distillers uses multiple centering rings throughout their column these days. I personally use ONE just above my sight glass ONLY to keep the reflux falling through the center of my sight glass rather than it flowing against the glass. Flowing against the glass annoys the piss out of me. I want to see it falling through the center. Rather than just a reducing collar, I cut it and bent every petal at an opposite angle in attempt to reduce vapor restriction.

As far as the the column being perfectly level, there was a thread here within a couple years ago where a guy deliberately tilted his column way off level and claimed to find no difference in performance. I still use a bubble level when I set up mine though. Why not right? I'll look for that link, but I can't find it right now.

[Stonecutter]

I believe that was a Yummyrum experiment SMF

[Salt Must Flow]

I believe that was a Yummyrum experiment SMF

Yeah I tried to find it, but can't find it right now.

[Yummyrum]

I believe that was a Yummyrum experiment SMF

Yeah I tried to find it, but can't find it right now.

This
viewtopic.php?p=7683367#p7683367

[Stonecutter]

I'm of the view there's to much open space, plus the band with the tabs really serve nothing, as the distillate will just follow the inside the band instead of the column.. waste of time and funds compared to some other packing doing a good job for the hobbyist..

Packing need to have the least amount of open space between the them for it to work at maximum efficient..

Mars

I know I’m ignorant and inexperienced but I wasn’t sure what this meant either.

Also,

Distillate will take the easiest path down, and centering ring just disrupt for a few mm only and create some lost of performance.. and the other reason is that boiler and column are never truly level, and the distillate will always travel to the off angle side.. something that is never talked about, being on level went refluxing..

Mars

Do or take the time to do such, and determine for one self,

Mars

I’m really trying to follow along Mars. I’m very new to the hobby and I know you’ve been a member here for quite a while. Honestly, to me this reflux science seems rather complex and that there are still plenty of mediums to be experimented with. I’m not saying it will but, if the Structured Packing that the OP talked about can positively contribute to the wealth of knowledge within this forum it will only make it that much easier for the individual hobbyists to perfect their craft. Just because somebody can achieve 95% doesn’t mean they know the why. The contributions of past members can give the weekend warrior a false sense of understanding. I know I’m guilty of it.

[eljefe3126]

I've now found a copy of Krell's Handbook of Laboratory Distillation (1982 edition). Figure 345, which has been reproduced in this forum several times, shows a HETP for SPP ranging from about 0.5 cm to about 3 cm. He also writes,

Helices of thin wire (Grosse-Oetringhaus) have an extremely high efficiencv. The author's experience shows that they can also deal with high loads. If such helices are to be resistant to corrosion they should he made of stainless steel (e.g. 18:8): furthermore, their manufacture to a constant length in sizes smaller than 2 mm is difficult. Their price is consequently high. On the other hand the efficiency of the small sizes (1.3-2 mm) is exceptional; an HETP of 1.0-1.6 cm can be obtained with them. The latter sizes are made of 0.15 -0.2 mm wire. For one litre of column space the number of rings required is approximately as follows:

2 mm 115,OOO
4 mm 12,600
20 mm 100

It was an obvious step also to make such helices of glass (Fenske helices). The writer carried out some tests on closely-wound glass spirals of 4~4x0.3 and 7 x 7 x 0.3 nun at atmospheric pressure with benzene-CCl, mixture and obtained the results shown in Table 71. They are available as both single and multi-turn helices.

Table 71 shows between 26 and 60 theoretical stages in a 1-meter column, which works out to an HETP of between 1.7 cm to 3.8 cm.

In the photo at the top of this thread, the two bundles of structured packing are made by Sulzer, and they advertise HETP of 3-10 cm for size DX (the big bundle) and 2-8 cm for size EX (the small bundle). The advantage of the structured packing is that it scales up without the HETP increasing, unlike most random packings. I suppose that might be of interest if you are planning on going toe-to-toe with Jack Daniels or Smirnov, but probably not at our scale.

I included the second paragraph about the glass helices because he calls them Fenske helices, and that seems to be what the industry calls our metal SPP. I can investigate what suppliers of will quote for "Fenske helices" if there is any interest.

[StillerBoy]

Unfortunately, valuable information such as column size and length are not mention in the copied..

So what was the column size that these Helices of thin wire used in.. as packing size efficiency is directly related to column size..

Mars

[Windy City]

In the chemical industry, this is what they call structured packing. It's layers of metal gauze (or plate), crimped into v-shaped corrugations at an angle to vertical of 45-60 degrees. Then each layer is placed back-to-back with the previous layer, so that droplets can bounce left or right as they descend like pinballs in a pachinko machine. The round bands have tabs that intercept droplets clinging to the wall of the column and redirect them to the interior where the packing is.

Has anyone here experimented with this stuff? It seems like it would be easy to make if one just had a means of corrugating strips of metal gauze.

image.png

Do they offer this in 4” and any idea how much it is??

[bunny]

https://www.sulzer.com/en/shared/produc ... 04daa16ae7

Looks like for 20-80mm columns.

[eljefe3126]

Unfortunately, valuable information such as column size and length are not mention in the copied..

So what was the column size that these Helices of thin wire used in.. as packing size efficiency is directly related to column size..

Figure 345, which has appeared in this forum, is for a column of 24 mm diameter and 0.5 meters tall. Infinite reflux ratio.

And I see that I misread the title for Figure 351 and wrongly assumed that was Table 71. So, Figure 351 is for little cylinders (he calls them "rings") of bronze gauze, 3mm x 3mm. That's what has 26-60 stages per meter (HETP = 1.7-3.8 cm). Data was gathered in a 100 mm x 1 meter column.

Table 71 is for the glass "Fenske helices". They measured HETP = 5.2 - 6.1 cm for 4 mm spirals, and HETP = 5.4 - 8.0 cm for 7 mm spirals. Column was 30 mm diameter x 0.92 meters tall.

Sadly, no column size data for the wire "Fenske helices".

[workpress]

Having just glanced into this discussion if one wanted to make their own crimped material you could simply order a paint tube crimping tool and I assume it would do the job quite well

workpress

image.png (46.93 KiB) Viewed 1129 times

[tiramisu]

Interesting thread. With metal 3d printing offering copper and stainless options I expect you could design some pretty darn impressive reflux packing ... but it doesn't seem necessary and would probably be prohibitively expensive. Cool Enginerding though.